Well in theory it should not work. It has to do something with modulated and unmodulated IR signals but I don't recall at this moment. Don't mess with the Sky IR receiver. The best thing would be to place an ir emmiter inside the equipment in front of the IR receiver. That would do the job just fine. In any case even if it does work (which most probably will not), you are scrapping the original remote so you have to put ALL the functions on your pronto + having the fear if the pronto RFX breaks down bye bye Sky until you can get it fixed! I hope that answers your question.
Demetris